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Soft devices, especially capacitive stress (or strain) sensors, are important for applications, including wearable medical monitoring, electronic skin, and soft robotics. The incorporation of liquid metal particles (LMPs) into highly deformable elastomers as inclusions ameliorates the mechanical compliance caused by a rigid filler. The high dielectric constant and liquid feature of LMPs are suitable for soft sensors with high sensitivity and a large real-time dynamic detection range. Here, a class of LM-elastomer composites are introduced with elastic and high dielectric properties, making them uniquely suitable for the application of soft stress sensors. The prepared stretchable soft stress sensor can detect the bending degree of the finger, monitor physiological signals in real time, and distinguish the vibration from the pronunciation of different letters. The nanoscale X-ray computational tomography (nano-CT) measurements indeed detect the changes of LMPs under stress, i.e., LMPs in the matrix distribute from uneven to relatively uniform, agglomerate, and even connect each other to have a conduction path in the composition with high LMP contents, which cause the changes in the physical properties of devices under operation. The cognition of LMP changes in composites under stress is instructive for promoting their further applications in the field of soft devices.

The interfacial energies between eutectic Ga-In-Sn liquid alloy and single nanoscopic asperities of SiOx, Au, and PtSi have been determined in the temperature range between room temperature and 90 °C by atomic force spectroscopy. For all asperities used here, we find that the interfacial tension of eutectic Ga-In-Sn liquid alloy is smaller than its free surface energy by a factor of two (for SiOx) to eight (for PtSi). Any significant oxide growth upon heating studied here was not detected, and the measured interfacial energies strongly depend on the chemistry of the asperities. We also observe a weak increase of the interfacial energy as a function of the temperature, which can be explained by the reactivity between SiOx and Ga and the occurrence of chemical segregation at the liquid alloy surface.

Design of stable high-performance heterogeneous catalysts has become crucial for efficient catalytic conversion of renewable biomass into high value-added chemicals. In this study, amphiphilic polymer support was synthesized by grafting hydrophobic groups onto hydrophilic cellulose nanocrystals and utilized as a support for PdNi alloy nanoparticles. The as-synthesized catalysts exhibited encouragingly high performance in the hydrodeoxygenation of vanillin under mild conditions.

The surface tension and viscosity of equilibrium and supercooled liquids of Cu50Zr50 were measured in the containerless electromagnetic levitator ISS-EML in the European space laboratory Columbus on board the International Space Station (ISS) under microgravity using high-speed camera recordings. From 1250 K to 1475 K, the surface tension follows the relation σ(T) = (1.58 ± 0.01) N/m – (3.1 ± 0.6) · 10−4 N/m · K · (T – 1209 K). A frequency shift correction was applied to remove the influence of sample rotation on the measured surface tension. Within the investigated temperature range, the viscosity can be expressed by an Arrhenius temperature dependence η(T) = η0 · exp(EA/kBT), with η0 = (0.08 ± 0.02) mPa·s and EA = (0.58 ± 0.03) eV.

Inspired by gradient materials in nature, advanced engineering components with controlled structural gradients have attracted substantial research interests due to their exceptional combinations of properties. However, it remains challenging to generate structural gradients that penetrate through bulk materials, which is essential for achieving enhanced mechanical properties in metallic materials. Here, we report practical strategies to design controllable structural gradients in bulk metallic glasses (BMGs). By adjusting processing conditions, including holding time and/or controlling temperatures, of cryogenic thermal cycling and fast cooling, two different types of gradient metallic glasses (GMGs) with spatially gradient-distributed free volume contents can be synthesized. Both mechanical testing and atomistic simulations demonstrate that the spatial gradient can endow GMGs with extra plasticity. Such an enhanced mechanical property is governed by the gradient-induced deflection of shear deformation that fundamentally suppresses the unlimited shear localization on a straight plane that would be expected in BMGs without such a gradient.

Coal liquefaction (CL) technology is a feasible solution to the energy crisis. The coal-to-liquid conversion includes direct CL (DCL) and indirect CL. Compared with the limited and unevenly distributed petroleum resources, the diesel from DCL (DDCL) has received worldwide attention since the beginning of this century and has been considered a substitute for diesel fuel. In this study, DDCL was regarded as a potential additive to improve the cold flow properties of petrodiesel. Other properties of the blending were also evaluated. When 40% DDCL was added to petrodiesel, the pour point (PP) reached − 31 °C, and the cold filter plugging point (CFPP) reached − 15 °C. The ΔPP and ΔCFPP decreased by 24 and 13 °C, respectively. The other properties, such as flash point and water content were not affected with the addition of DDCL. The cetane number of the blending were decreased but can be solved by adding fatty acid esters easily. The blending could be used in most climatic zones in the world, except the polar regions. In addition, Crystallization behavior was investigated via differential scanning calorimetry (DSC), and find that petrodiesel blended with 40% DDCL is more stable than blended with 10% and 20% DDCL.

Mixed and ground activated snail shell and kaolin catalysts impregnated with KBr were investigated. The snail shell and kaolin were calcined, mixed, and ground prior to immersion with KBr solution and subsequent activation at 500 °C for 3 h. The precursor and catalysts were characterized by thermal gravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and Brunauer–Emmett–Teller surface area. The catalytic performance of the prepared catalysts was evaluated by transesterification of soybean oil with methanol. The effects of various parameters on biodiesel yield were investigated. A biodiesel yield of 98.5% was achieved using the catalyst prepared by 40% KBr-immersed, mixed, and ground snail shell and kaolin, which were activated at 500 °C. The transesterification conditions were as follows: reaction temperature, 65 °C; reaction time, 2 h; methanol-to-soybean oil molar ratio, 6:1; and catalyst amount (relative to the weight of soybean oil), 2.0 wt%. The solid catalyst could be reused for four times, and biodiesel yield remained over 73.6% for the fourth time.

Graphene/metal-oxide nanocomposites have been widely studied as anode materials for lithium ion batteries and exhibit much higher lithium storage capacity beyond their theoretical capacity through mechanisms that are still poorly understood. In this research, we present a comprehensive understanding in microscale of the discharge process of graphene/TiO2 containing surface, bulk, and interfacial lithium storage based on the first-principles total energy calculations. It is revealed that interfacial oxygen atoms play an important role on the interfacial lithium storage. The additional capacity originating from surface and interfacial lithium storage via an electrostatic capacitive mechanism contributes significantly to the electrode capacity. The research demonstrates that for nanocomposites used in energy storage materials, electrode and capacitor behavior could be optimized to develop high-performance electrode materials with the balance of storage capacity and rate.

Temperature-dependent magnetization and magnon Raman spectra were measured for anti-ferromagnetic NiO-nanoflowers. The results show several new magnetic behaviors, including the appearance of a ferromagnetic phase, a reduced Neel temperature (TN) and a reduced Curie temperature (TC). The temperature dependencies of the double magnon (2M) Raman wavenumber and intensity are similar to those of magnetization. A magnetic granules model (MGM) consisted of a crystalline core enclosed by a shell is proposed. The model suggests that the large quantity of spins induced by specific surface effect in the shell plays a key role in nano-magnetism. Based on the MGM, the micro-mechanism of the observed new magnetic behavior is understood by the magnon Raman spectra. The MGM is based on the general features of magnetic nano-particles, and thus it should be generally applicable to common magnetic nano-particles. Copyright © 2014 John Wiley & Sons, Ltd.

In order to develop new Al alloy, the quasi-static and dynamic compression deformation behavior of an advanced Al-Mg alloy, which contained Zn and rare earth, were investigated. Deformed microstructures in the shear bands of this alloy were characterized by optical microscope. Results show that the compressive strengths increase with strain and strain rates being increased, and microstructures of deformed Al-Mg alloy along compression directions are sensitive to strain rates. The distorted deformation twins near the deformed band can be formed under low strain rate of 5.6×10-3 s-1, while multiple shear bands slipping can be induced by dynamic deformation under high strain rates from 1.9×103 s-1 to 5×103 s-1. Therefore, compressive strength and fracture strain of dynamic deformation are higher than that of the quasi-static deformation, which is attributed to the strain hardening and grain refining in the multiple shear bands.

Based on first-principles electronic structure calculations and molecular dynamics simulations, a possible reaction pathway for fabricating half-metallic Mo-borine sandwich molecular wires on a hydrogen-passivated Si(001) surface is presented. The molecular wire is chemically bonded to the silicon surface and is stable up to room temperature. Interestingly, the essential properties of the molecular wire are not significantly affected by the Si substrate. Furthermore, their electronic and magnetic properties are tunable by an external electric field, which allows the molecular wire to function as a molecular switch or a basic component for information storage devices, leading to applications in future molecular electronic and spintronic devices.

Bulk metallic glasses (BMGs) of Cu45Zr48-xAl7Tix with x= 0, 1.5, and 3 at.% were prepared by copper mould casting. The corrosion resistance of the BMGs with different Ti contents was examined by potentiodynamic polarization tests and weight loss measurements in 1 N NaOH, 1 N H2SO4, 1 N H2SO4 + 0.01 N NaCl and 0.5 N NaCl solutions, respectively. The newly-developed BMGs’ corrosion resistance in Cl-- or both H+ and Cl--ions containing solutions can be greatly enhanced. The influence of Ti addition on glass forming ability (GFA) and thermal stability was investigated by x-ray diffraction and differential scanning calorimetry in detail. The alloy containing 1.5 at.% Ti exhibits the largest GFA, the critical size comes up to 10 mm in diameter.

In order to obtain the directional microstructure of different supersaturation and growing velocity, three simulations is calculated with different initial temperature. When the initial temperature is 1576K, and the supersaturation and growing velocity are smaller. The average space length of columnar crystals is bigger, and the directional microstructure grows by the wide columnar crystals. Microsegregation is smaller; when the initial temperature is 1574K, the supersaturation and growing velocity increase. when the initial temperature falls to 1566K, the planar interface comes back, and microsegregation decreases rapidly. The directional microstructure grows by the thinnest columnar crystals. At the same time, the transverse solute profiles and solute boundary layer are also talked in this paper.

Phase-field method can be used to describe the complicated morphologies of crystal growth without explicitly tracking the complex phase boundaries. The conformation of volume free energy is very important for microstructure simulation with phase-field method. However, the conformation of volume free energy is still correspondingly simple and ideal at present. In this paper, a new conformation method of free energy is mentioned. Free energy of each phase at appointed states is calculated by Thermo-Calc software. In order to avoided calculation, free energy of each phase is fitted by multiple-point function according to sub- regular solution model. It is obtained that the free energy data and phase graph data of α phase, θ phase and L phase in the extension, temperature (791-841) K and component (0-35)Cu(at.%) with Al-Cu eutectic alloy. The new phase model is also founded, and used to calculate microstructure evolution of Al-Cu eutectic alloy.

In this study W was found to have strong effects on solidification structure of the binary alloy. Based 0.5 W0、W0 and 1.5W0 base W0, three conditions with free energy base W equal to 0.5 W0, W0 and 1.5W0 respectively were computed. The results showed that the variation of energy base contributed a lot to the development of side branches of equiaxed dendrite structures, the lower W, the more developed side branches, the higher W, the more restrained side branches. Furthermore, the effects of boundary layer thickness δ on solidification structures were also studied. It is found that when the layer thickness δ is as small as Δx/0.94, computational errors occurred at the base of the dendrite and when the layer thickness δ is as big as Δx/0.54, some irreal phenomena, such as coarsened dendrite trunks and maladjusted side branches, could be caused. Further study on space step Δx showed that bigger space steps made higher computational errors. It is given that the relationships among phase-field perturbation, space step and solidification structure.

In this paper, microstructure of AL-Cu eutectic alloy is simulated by improving Nestler’s multiphase-field model. The exact physical parameters are used in multiphase-field model, and obtained the steady calculational results. In this numerical calculation, AL and AL2Cu are regard as two independent components. The eutectic microstructure is regard as an admixture of single phase α (AL) and single phase θ (AL2Cu). Using the model, steady eutectic layered growth is simulated, and the simulated results agree well with the solidification theory. At the same time, the stochastic noise is introduced, and eutectic free layered growth microstructure is simulated. The microstructure of primary dendritic crystal and pseudoeutectic is also simulated by enlarging the calculational interval scale, and obtained a better result.

Maghemite (γ-Fe2O3) is a very common mineral at the earth’s surface and also an important material for making music and video tapes. Maghemite is usually synthesized from magnetite under oxidizing conditions after a few hours or a few days below a temperature of 300°C. The magnetic property of thermal instability and the chemical action after heating is an important character for maghemite. That is, it will become hematite in certain proportion after being heated above 250°C. Maghemite is therefore actually unable to have its Curie temperature measured. But late using synthetic sample, maghemite was further found partially thermal stable with a measurable Curie temperature ∼645°C. During our thermally magnetic experiments for a set of synthetic magnetite, we found that extra fined grain size (pseudo single domain (PSD) and small multi-domain (MD), mainly 1–10 μm) magnetite was formed to a completely thermally stable maghemite. This maghemite can also be produced by heating the same powder up to 700°C in an oven and keeping this temperature for 10 min, then cooling it down. When the generated maghemite by these two ways is heated from room temperature to 700°C, it shows almost fully reversible, or thermally stable. We used X-ray powder diffraction and Mossbauer spectroscopy to confirm the identity of this maghemite and compared its magnetic hysteresis, high temperature magnetization, low temperature thermal demagnetization, and low temperature susceptibility with those of the original preheated magnetite. Such quickly oxidized maghemite by heating to high temperature implies some types of maghemite formed in certain natural condition can carry a thermal remnant magnetization (TRM). Four types of maghemite were characterized and discussed according to their thermal stability. Among them, partially stable and fully thermally stable maghemite after heating should possess capability of carrying TRM. There is possibly a compensation of synthetizing maghemite between heating temperature and heating duration. The thermal stability of maghemite may be affected by a few factors, such as its purity (stoichiometry), heating temperature and duration. The grain size may be one of important factors. Maghemite might be similar to magnetite, having various magnetic properties corresponding to its grain size categories such as superparamagnetic (SP), single domain (SD) and MD. Low temperature measurement for PSD fine grain of synthetic magnetite shows a phenomenon of Verwey transition “suppressed”, its fundamental causes could be that the core diameter of oxidized magnetite is actually reach or approach SD size, so that its Verwey transition is shown “suppressed”.

Kinetic surface roughening of electrodeposited PdP and NiP amorphous films were investigated by atomic force microscopy and X-rays phase-contrast radiography. Anomalous scaling of the interface width was observed for PdP system, with H = 0.75 ± 0.06, βloc = 0.49 ± 0.07 and β = 0.38 ± 0.08. In contrast, NiP system shows normal scaling behavior, with H = 0.70 ± 0.02 and β = 0.16 ± 0.03. The results suggest that surface roughening during film growth is strongly influenced by local behaviors like hydrogen evolution reaction, which shifts surface roughening from normal scaling in NiP to anomalous scaling in PdP. Keywords: Electrodeposition, Amorphous alloys, Kinetic roughening, Synchrotron, Phase-contrast radiography, HER

Based on the theoretical analysis of the molecular dynamics simulation of sliding contact between a single micro-particle and a smooth flat surface, a new dominant mechanism of viscous flow of the amorphous layer on wafer surface for the material removal in chemical mechanical polishing (CMP) process is proposed. Furthermore, a new mathematical model characterizing the material removal rate in CMP process is developed by using micro-contact mechanics and particle size distribution theory on the basis of this mechanism. Particularly, a new important parameter k, representing the ability to remove the amorphous layer from wafer surface by a single particle, is firstly put forward and integrated in the model. The model not only incorporates the mechanical effects of the slurry particles and chemical role of the slurry, but also includes the influences of other important factors on CMP process such as wafer material properties, pad surface profiles and operating variables. The model has also been verified by the experiments shows good agreement with those experimental data in the same CMP conditions. This research will provide a new platform for further investigation in CMP mechanism of material removal.

This paper proposed a novel mathematical model to fully describe the influence of chemical mechanical synergy (CMS) on material removal in chemical mechanical polishing (CMP) of wafer at molecular scale. A general equation is derived on the basis of molecular scale removal mechanism and micro-contact theory. It is shown that the relative velocity-removal rate relation follows the trend similar to that observed from the effects of pressure and oxidizer concentration on material removal not discussed by previous models. Furthermore, the parameters of the poling pad, wafer and operating variables in CMP process that are not available in other complex models are formulated into the model. The model predictions are good agreement with the published experimental data. In addition, the present study also lends further credence to the molecular scale removal mechanism of CMP process in addition to its underlying theoretical foundation.

A new stationary-frame AC current control strategy that can eliminate steady-state errors is discussed and applied to the control of transverse flux permanent-magnet machine (TFPM). Based on the principle of modulation and demodulation, this AC controller can achieve the same frequency response characteristic as the equivalent DC controller. Validity of the TFPM control system using this current control strategy is confirmed with simulation results.

Ligand‐free Suzuki reactions catalyzed by Pd/C can be efficiently performed in TX100 microemulsions. A number of aryl halides, including aryl iodides, bromides, and chlorides, were coupled with arylboronic acids smoothly and efficiently to produce good to excellent yields.

Ullmann reactions catalyzed by palladium without other reducing agents were performed in microemulsion and the microemulsion was found to be the reducing agent in the Ullmann coupling of a broad spectrum of aryl halides.

Rutile films were deposited on polyethylene terephatalate (PET), polytetrafluoroethylene (PTFE), Silicone, poly6-caprolactam (Nylon6), polyhexamethylene adipamide (Nylon6,6) and Nylon fiber substrates using 0.03 M TiOSO4 and 0.03 M H2O2 aqueous solution at 80°C for 24 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF).

Rutile films were deposited on poly-l-lactide (PLLA) substrates using 0.5 M titanium tetrachloride aqueous solution at 40 °C for 72 h. The rutile films exhibited excellent in vitro bioactivity as they induced apatite deposition in a simulated body fluid (SBF) within 3 days. This simple treatment provided an effective route to synthesize bioactive and biodegradable scaffolds.

Heterogeneous Heck reaction catalyzed by Pd (NH3)4 2+‐Na‐Y zeolite in the presence of K2CO3 as the base has been carried out in an oil‐in‐water microemulsion based on Triton X10 at 80°C.

In the present paper, the surface tensions and interfacial energies for pure metals and alloys for different structures were predicted by combining with the evaluated thermodynamic parameters in the framework of the CALPHAD (Calculation of Phase Diagrams) method. It is shown that the calculated results are in good agreement with the existing experimental data. On the basis of the predicted values of surface tension and interfacial energy, the phase stability and phase diagram with nano-size particles can be calculated by considering the Gibbs-Thomson equation. The calculated results for pure Fe indicate that the fcc phase is more stable with the decreasing of size of particles, which is in agreement with the experimental data reported, and the phase diagram with nano-size particle can be calculated.

A novel embedded-type permanent magnetic motor for hybrid motorcycle, which employs asymmetric design of eccentric air-gap, is proposed in the paper. This special design of air-gap well conforms to the mono-directional operation characteristic of motorcycle and effectively suppresses the distortion of air-gap magnetic field caused by armature reaction. Hence the torque ripple is reduced. A drive system consisting of the newly-designed Nd-Fe-B permanent magnet synchronous motor and parallel-MOSFET three-phase inverter for hybrid motorcycle propulsion is established. Wide-range speed operation is realized through a simple and novel control strategy. Computer simulation is described and experimental results given to verify the practicality of the proposed motor design and control strategy.

The influence of large number of heating and cooling cycles on the nucleation and hence on the undercooling of Pd40Cu30Ni10P20 melt has been investigated by differential scanning calorimety. The repeated undercooling measurements allow the investigation of the stochastic nature of the nucleation process. It is found that the value of the undercooling monotonically decreases with increasing cycle number up to about 100 cycles. The melting temperature of the alloy on the other hand remains constant up to 60 cycles and then it increases by 85 °C. Structure characterisation by X-ray diffraction and scanning electron microscopy measurements reveals that a Cu-O oxide layer is gradually formed with increasing cycle number. This causes a depletion of copper in the interior of the sample and therefore decreases the glass forming ability of the alloy. A correlation of cycling dependence of melting, liquidus, and nucleation temperatures with the microstructure evolution is presented. References

The geometrical feature of the skewed rotor slots in induction motors makes the 2-dimensional (2-D) finite element method (FEM) not directly applicable. Based on the multi-slice model in this paper, a time stepping 2-D eddy-current FEM is described to study the steady-state operation and the starting process of induction machines with skewed rotor slots. The fields of the multi-slices are solved in parallel, and thus the effects of skewed slots and eddy-current can be taken into account directly. The basic formulas for the multi-slice model are derived. Special technique to reduce computation time in solving the coupled system equations is also described. The results obtained by using the program developed have very good correlation with the test data.

The torque output in a permanent magnet brushless DC motor (BLDCM) is usually controlled by regulating the motor phase currents. In this paper, three kinds of PWM strategies together with some critical review on traditional current measurements in a BLDCM drive system are discussed. A novel method for assessing the PWM information and measuring the motor phase currents by a dc link current sensor is proposed. An attractive feature of the proposed method is the simplicity with the current sample processing because there is no need to incorporate the conduction information of the power switches or diodes. Only the single sided PWM or the double sided complementary PWM is needed with the proposed technique.